Process for the manufacture of low molecular weight polyphenylene ether resins

Abstract

The invention relates to a novel process for the manufacture of very low molecular weight polyphenylene ether resin, typically within the intrinsic viscosity range of about 0.08 dl/g to about 0.16 dl/g as measured in chloroform at 25° C. The method preferably comprises 2,6-dimethylphenol as a monovalent phenol species. The invention also relates to the polyphenylene ether resin made by the process as well as blends and articles containing the polyphenylene ether resin made by the process.

What is claimed:  
     
       1. A method to prepare a polyphenylene ether resin that has less than about a 10% drop in intrinsic viscosity after equilibration, said method comprising oxidative coupling in a reaction solution at least one monovalent phenol species using an oxygen containing gas and a complex metal catalyst to produce a polyphenylene ether resin having an intrinsic viscosity within the range of about 0.08 dl/g to about 0.16 dl/g as measured in chloroform at 25° C.; equilibrating a metal chelating agent with the complex metal catalyst to prepare a chelated complex metal catalyst; recovering the chelated complex metal catalyst with an aqueous containing solution; and isolating the polyphenylene ether resin through devolatilization of the reaction solvent. 
     
     
       2. The method of claim  1  wherein the polyphenylene ether resin has less than about a 10% drop in intrinsic viscosity after equilibration. 
     
     
       3. The method of claim  1  wherein the monovalent phenol species comprises 2,6-dimethylphenol. 
     
     
       4. The method of claim  1  wherein the devolatilization is accomplished at least in part with a devolatilization extruder. 
     
     
       5. The method of claim  4  wherein the devolatilization extruder is at least partly operated at between about 185-220° C. 
     
     
       6. The method of claim  4  wherein the reaction solution has a solids level of at least about 65% before feeding into the devolatilization extruder. 
     
     
       7. The method of claim  1  wherein the polyphenylene ether resin has an incorporated amine content of less than about 0.3% by weight based on the weight of the polyphenylene ether resin. 
     
     
       8. The method of claim  1  further comprising underwater pelletizing of the polyphenylene ether resin. 
     
     
       9. A polyphenylene ether resin made by the method of claim  1 .